An Architecture for Differentiated Services
RFC 2475

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Network Working Group                                        S. Blake
Request for Comments: 2475            Torrent Networking Technologies
Category: Informational                                      D. Black
                                                      EMC Corporation
                                                           M. Carlson
                                                     Sun Microsystems
                                                            E. Davies
                                                            Nortel UK
                                                              Z. Wang
                                        Bell Labs Lucent Technologies
                                                             W. Weiss
                                                  Lucent Technologies
                                                        December 1998

              An Architecture for Differentiated Services

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (1998).  All Rights Reserved.

Abstract

   This document defines an architecture for implementing scalable
   service differentiation in the Internet.  This architecture achieves
   scalability by aggregating traffic classification state which is
   conveyed by means of IP-layer packet marking using the DS field
   [DSFIELD].  Packets are classified and marked to receive a particular
   per-hop forwarding behavior on nodes along their path.  Sophisticated
   classification, marking, policing, and shaping operations need only
   be implemented at network boundaries or hosts.  Network resources are
   allocated to traffic streams by service provisioning policies which
   govern how traffic is marked and conditioned upon entry to a
   differentiated services-capable network, and how that traffic is
   forwarded within that network.  A wide variety of services can be
   implemented on top of these building blocks.

Blake, et. al.               Informational                      [Page 1]
RFC 2475        Architecture for Differentiated Services   December 1998

Table of Contents

   1.  Introduction .................................................  2
     1.1  Overview  .................................................  2
     1.2  Terminology ...............................................  4
     1.3  Requirements ..............................................  8
     1.4  Comparisons with Other Approaches .........................  9
   2.  Differentiated Services Architectural Model .................. 12
     2.1  Differentiated Services Domain ............................ 12
       2.1.1  DS Boundary Nodes and Interior Nodes .................. 12
       2.1.2  DS Ingress Node and Egress Node ....................... 13
     2.2  Differentiated Services Region ............................ 13
     2.3  Traffic Classification and Conditioning ................... 14
       2.3.1  Classifiers ........................................... 14
       2.3.2  Traffic Profiles ...................................... 15
       2.3.3  Traffic Conditioners .................................. 15
         2.3.3.1  Meters ............................................ 16
         2.3.3.2  Markers ........................................... 16
         2.3.3.3  Shapers ........................................... 17
         2.3.3.4  Droppers .......................................... 17
       2.3.4  Location of Traffic Conditioners and MF Classifiers ... 17
         2.3.4.1  Within the Source Domain .......................... 17
         2.3.4.2  At the Boundary of a DS Domain .................... 18
         2.3.4.3  In non-DS-Capable Domains ......................... 18
         2.3.4.4  In Interior DS Nodes .............................. 19
     2.4  Per-Hop Behaviors ......................................... 19
     2.5  Network Resource Allocation ............................... 20
   3.  Per-Hop Behavior Specification Guidelines .................... 21
   4.  Interoperability with Non-Differentiated Services-Compliant
       Nodes ........................................................ 25
   5.  Multicast Considerations ..................................... 26
   6.  Security and Tunneling Considerations ........................ 27
     6.1  Theft and Denial of Service ............................... 28
     6.2  IPsec and Tunneling Interactions .......................... 30
     6.3  Auditing .................................................. 32
   7.  Acknowledgements ............................................. 32
   8.  References ................................................... 33
   Authors' Addresses ............................................... 34
   Full Copyright Statement ......................................... 36